How to Validate like this 10.05 & 100.05

Hello Developers,

how i validate How to Validate Text box value like this 10.05 & 100.05Numbers and Dot only allowed.1.Textbox1=10.05 or xx.yy //first two digit int last two digit decimal2.Textbox1=100.05 or xxx.yy//first three digit int last two digit decimalin 1 and 2 2 secimal values is must.if there is no decimal value or no decimal value without extension of 2 it should be =(validate message) validate please enter valid decimal with extension of 2 decimal value.

12222=incorrect.1.445=incorrect..5555=incorect.333.6=incorrect.

.33=correct10.23=correct.i have tried If anyone know this please tell me some idea.